In motor assembly situations, it is typically necessary to assemble a motor shaft with a motor housing. Additionally, it is often necessary to affix a component to the motor shaft after the motor shaft and the motor housing are assembled.
One method of assembling a motor shaft in a motor housing includes installing a snap ring into a groove in the motor shaft. The snap ring serves as a retainer for a bearing which is pressed onto the motor shaft and rests against the snap ring. The motor shaft and its associated components are installed into the motor housing with one end of the shaft protruding from the housing. A barrel spacer is then fitted onto the shaft next to the bearing. After placement on the shaft, the barrel spacer also protrudes from the motor housing. A first washer is slid onto the protruding end of the shaft and abuts the barrel spacer. In certain applications a component, such as an impeller, may also be slid onto the protruding end of the shaft into abutment with the first washer. A second washer is placed onto the motor shaft to sandwich the component between two washers. A hex nut is then threaded onto the end of the protruding shaft in order to hold all components on the shaft together in an axial direction against the snap ring. The threaded nut serves to apply pressure to the washers, which in turn hold the impeller to insure that the impeller rotates as the motor shaft rotates.
The previously described method has disadvantages. First, the snap ring and groove method of retaining the bearing is not an optimal solution in terms of quality. Secondly, it is not easy to tighten the nut onto the motor shaft, because the shaft has a tendency to rotate as the nut is tightened.